Latrepirdine ( INN, also known as dimebolin and sold as Dimebon) is an

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

drug A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhala ...

which has been used clinically in

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

since 1983. Research was conducted in both Russia and western nations into potential applications as a neuroprotective drug to treat

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As ...

and, possibly, as a

nootropic Nootropics ( , or ) (colloquial: smart drugs and cognitive enhancers, similar to adaptogens) are a wide range of natural or synthetic dietary supplement, supplements or drugs and other substances that are claimed to improve cognitive function ...

, as well. After a major phase III clinical trial for Alzheimer's disease (AD) treatment failed to show any benefit, three other AD trials continued.Novel Alzheimer's Drug Flops
''MedPage Today'', March 03, 2010 Major industry-based development in this indication essentially stopped after another Phase III trial suffered the same fate in 2012.Sweetlove M: Phase III CONCERT Trial of Latrepirdine. Negative results. Pharm Med 2012;26(2):113-115 Latrepirdine failed in the phase III trial for Huntington disease.

Uses

Latrepirdine is an orally active, small molecule compound that has been shown to inhibit brain cell death in animal models of Alzheimer's disease and

Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an uns ...

. Research suggests it may also have cognition-enhancing effects in healthy individuals, in the absence of neurodegenerative disease pathology. However, because of negative results in human clinical trials, the drug remains unlicensed for any neurodegenerative condition.

Alzheimer's disease: failed in Phase III clinical trials

Latrepirdine attracted renewed interest in 2009 after being shown in small preclinical trials to have positive effects on persons suffering from

Alzheimer's Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As t ...

disease. Animal studies showing potential beneficial effects on Alzheimer's disease models were shown in Russian research in 2000. Preliminary results from human trials have also been promising. In an initial six-month phase II trial, results have shown significant improvement over placebo at 12 months. Latrepirdine showed promising results in a phase III-equivalent, double-blind trial in Russia with mild–moderate stage patients. In April 2009, Pfizer and Medivation initiated a phase III trial (CONCERT study) aiming for FDA approval. In March 2010, Pfizer announced that this clinical trial failed to show any benefit for the treatment of Alzheimer's disease patients. Numerous phase III trials for AD were recruiting in 2009. In July 2009, Pfizer and Medivation announced that "latrepirdine" was to be the proposed international nonproprietary name for latrepirdine for the treatment of Alzheimer's. In March 2010, the results of a clinical trial phase III were released; the investigational Alzheimer's disease drug dimebon failed in the pivotal CONNECTION trial of patients with mild-to-moderate disease. With CONCERT, the remaining Pfizer and Medivation Phase III trial for latrepirdine in Alzheimer's disease failed in 2012, effectively ending the development in this indication. A Cochrane meta-analysis of the three pivotal phase III efficacy trials found no significant effect of latrepirdine on cognition and function in mild-to-moderate Alzheimer's patients, though there appears to be a modest benefit for overall behavior disturbances.

Huntington's disease

In April 2011, latrepirdine failed in a phase III clinical trial of patients affected with Huntington's disease. The trial was sponsored by Medivation Inc. and

Pfizer Pfizer Inc. ( ) is an American multinational pharmaceutical and biotechnology corporation headquartered on 42nd Street in Manhattan, New York City. The company was established in 1849 in New York by two German entrepreneurs, Charles Pfize ...

Pharmacology

Latrepirdine appears to operate through multiple mechanisms of action, both blocking the action of neurotoxic

beta-amyloid Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid precursor protein (APP), which is ...

proteins and inhibiting L-type

calcium channels A calcium channel is an ion channel which shows selective permeability to calcium ions. It is sometimes synonymous with voltage-gated calcium channel, although there are also ligand-gated calcium channels. Comparison tables The following tables ex ...

, modulating the action of AMPA and NMDA

glutamate receptor Glutamate receptors are synaptic and non synaptic receptors located primarily on the membranes of neuronal and glial cells. Glutamate (the conjugate base of glutamic acid) is abundant in the human body, but particularly in the nervous system ...

s, and may exert a neuroprotective effect by blocking a novel target that involves mitochondrial pores, which are believed to play a role in the cell death that is associated with neurodegenerative diseases and the aging process. It also blocks a number of other receptors, including

α-adrenergic The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like bet ...

, 5-HT_2C, 5-HT_5A, and 5-HT₆. It is of significance to note latrepirdine lacks any

anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous sys ...

effects.

References

{{Tricyclics Nootropics H1 receptor antagonists Pyridines Pyridoindoles Russian drugs Soviet inventions Drugs in the Soviet Union Gamma-Carbolines

Uses

Alzheimer's disease: failed in Phase III clinical trials

Huntington's disease

Pharmacology

See also

References